Truck platform construction

ABSTRACT

There is provided a truck platform construction in which when an external force acts on a platform from the rear side, a width change portion surely absorbs the energy thereof to prevent the deformation of a cab without marring the appearance of a top rail. A side panel erected at both side edges of a platform has an outer panel which constitutes a side external wall of the platform and is formed with an outer bent element at the upper edge thereof and an inner panel which constitutes a side internal wall of the platform. A top rail is formed by fixing the outer bent element onto the inner panel. At the rear part of the top rail, a width change portion in which the width of the top rail changes is formed, and the width of the width change portion increases gradually toward the rear of a truck.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims Paris Convention priority of JapaneseApplication No. 2003-208379 filed Aug. 22, 2003, the entire disclosureof which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a construction of a side panel erectedat both side edges of a truck platform.

2. Description of the Related Art

A truck platform side wall construction has conventionally been known inwhich a side wall erected at both side edges of a truck platformincludes an outer panel constituting a side external wall of theplatform and an inner panel constituting a side internal wall thereof,and each of the panels has a top portion, a depending portion thatdepends downward from the top portion on the inside of the platform, andan external wall portion extending downward from a vehicle outside endportion of the top portion (for example, refer to claim, Specification3rd line to 18th line on page 9, FIG. 2, and FIG. 5 of UnexaminedJapanese Utility Model Publication No. 63-110176). In this truckplatform side wall construction, the top portion of inner panel isarranged under the top portion of outer panel, and the depending portionof outer panel and the depending portion of inner panel are lapped oneach other in a state in which the depending portion of outer panel ispositioned on the inside of platform, the lapped portions being spotwelded. The top portion of inner panel is formed with a plurality ofprotrusions that project upward and are arranged in the longitudinaldirection of platform, and these protrusions are brought into contactwith the lower surface of outer panel top portion. A gap is formedbetween the top portions of both panels excluding the contact portionsand between the external wall portions near the top portions, and anotch is formed in a portion adjacent to the protrusion in the dependingportion of inner panel.

In the truck platform side wall construction configured as describedabove, when an external force acts on the platform from the rear side,stress is concentrated at the notch, and the side wall is deformed inthis portion, by which the energy of the external force is absorbed. Asa result, the platform is prevented from hitting a cab with a largeforce. Also, the deformation of cab can be prevented without a strongreinforcing member provided at the rear part of the cab, so that themanufacturing cost of cab can be reduced.

On the other hand, there has been disclosed a truck platformconstruction in which recesses are formed at predetermined intervals inthe longitudinal direction of platform in inside projecting inclinedsurfaces of inner panels of the right and left side panels of platform;a rope hook of a U shape in plan view is fixed in the recess; and astake insertion hole is formed in a top rail portion of side panel justabove the rope hook (for example, refer to claim, Specification 15thline on page 3 to 5th line on page 4, and FIGS. 1 to 6 of UnexaminedJapanese Utility Model Publication No. 3-43089).

In the truck platform construction configured as described above, thestake is inserted through the stake insertion hole formed in the toprail portion of side panel, and the lower end of stake is fitted in aninside space of rope hook in the recess, by which a stake deck can beformed. Also, by hooking a rope to the rope hook, a cargo can be fixed,which is the inherent object of the rope hook. Further, by placing abridging material between the rope hooks in the recesses provided in theright and left side panels, cargoes can be stacked up in two tiers.

However, in the conventional truck platform side wall constructiondescribed in Unexamined Japanese Utility Model Publication No.63-110176, the notch is formed only in the inner panel, and no notch isformed in the outer panel. Therefore, when an external force acts on theplatform from the rear side, energy is not absorbed sufficiently in somecases.

Also, in the conventional truck platform side wall constructiondescribed in Unexamined Japanese Utility Model Publication No.63-110176, when the inner panel is formed by a synthetic resin toimprove the appearance of the inside of the platform, the lapped portionof the depending portion of outer panel and the depending portion ofinner panel must be fixed to each other by using bolts and nuts in placeof spot welding. In this case, since the shape of inner panel isintricate, the formability of inner panel is decreased, and also, asdescribed above, when an external force acts on the platform from therear side, energy is not absorbed sufficiently in some cases.

Further, in the conventional truck platform construction described inUnexamined Japanese Utility Model Publication No. 3-43089, the holeformed in the top rail portion of side panel is provided only to insertthe stake for constructing the stake deck, and there is no technicalconcept that when an external force acts on the platform from the rearside, the energy thereof is absorbed. Since the hole is exposed in thetop rail portion, there arises a problem in that the appearance of toprail portion is marred.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a truck platformconstruction in which when an external force acts on a platform from therear side, a width change portion surely absorbs the energy thereof toprevent the deformation of a cab without marring the appearance of a toprail.

Another object of the present invention is to provide a truck platformconstruction in which when an inner panel or an outer panel is formed bya synthetic resin, the formability thereof is improved, and also when anexternal force acts on the platform from the rear side, energy thereofis absorbed surely by the width change portion to prevent the cab frombeing deformed.

The invention of a first aspect provides an improvement in a truckplatform construction in which a side panel erected at both side edgesof a platform on the back surface of a cab has an outer panel whichconstitutes a side external wall of the platform and is formed with anouter bent element at the upper edge thereof and an inner panel whichconstitutes a side internal wall of the platform, and a top rail isformed by fixing the outer bent element onto the inner panel.

The characteristic configuration of the invention of the first aspect issuch that a width change portion in which the width of the top railchanges is formed at the rear part of the top rail, and the width of thewidth change portion increases gradually toward the rear of the truck.

In the truck platform construction described in the invention of thefirst aspect, when an external force acts on the platform from the rearside, stress is concentrated at the front part of the width changeportion, so that the side panel is deformed in this portion. As aresult, the energy of the aforementioned external force can surely beabsorbed by the deformation of the platform, so that the external forcetransmitted to the cab decreases, by which the deformation of the cabcan be prevented. Also, the width change portion is provided at the rearpart of the truck and is distant from the cab, so that the deformationof the platform exerts no influence on the cab.

The invention of a second aspect is characterized in that in theinvention of the first aspect, a terminal end of spread of the widthchange portion coincides with the side front end of a tail gate forclosing an opening at the rear end of the platform.

In the truck platform construction described in the invention of thesecond aspect, since the terminal end of spread of the width changeportion coincides with the side front end of a tail gate for closing anopening at the rear end of the platform, the appearance of the rear endcorner portion of platform can be improved, and cargoes can easily beput in or taken out through the opening at the rear end of the platform.Further, since the platform width at the rear part of the platformincreases, a large storage space can be secured.

The invention of a third aspect is characterized in that in theinvention of the first aspect, a rear reinforcing member is provided onthe rear end lower surface of the platform so as to extend in thevehicle width direction, and at least the front part of the width changeportion is formed at a position at which it does not overlap with therear reinforcing member in a plan view.

In the truck platform construction described in the invention of thethird aspect, since at least the front part of the width change portionis positioned in front of the rear reinforcing member in plan view, therigidity of the platform can be changed greatly at the front part of thewidth change portion.

The invention of a fourth aspect is characterized in that in theinvention of the first aspect, a weak portion for change portion isformed in the width change portion.

In the truck platform construction described in the invention of thefourth aspect, since the weak portion for change portion is formed inthe width change portion, stress is further concentrated at thisportion.

The invention of a fifth aspect provides an improvement in a truckplatform construction in which a side panel erected at both side edgesof a platform on the back surface of a cab has an outer panel whichconstitutes a side external wall of the platform and an inner panelwhich constitutes a side internal wall of the platform; the outer panelhas an outer bent element formed at the upper edge thereof and an outerthrough hole formed in the outer bent element; the inner panel has aninner through hole formed at the upper part thereof so that the holecenter is aligned with that of the outer through hole; and a fastener isinserted through the outer through hole and the inner through hole tofix the inner panel to the outer panel, whereby a top rail is formed.

The characteristic configuration of the invention of the fifth aspect issuch that either one or both of the inner panel and the outer panel areformed of a synthetic resin, and a weak portion for through hole isformed at the peripheral edge of either one or both of the inner throughhole in the inner panel and the outer through hole in the outer panel.

In the truck platform construction described in the invention of thefifth aspect, when an external force acts on the platform from the rearside, stress is concentrated at the weak portion for through hole, andhence a crack is generated in this portion, so that the fastener comesoff the inner panel, and the side panel becomes easy to deform. As aresult, the energy of the aforementioned external force can surely beabsorbed by the deformation of the platform, so that the external forcetransmitted to the cab decreases, by which the deformation of the cabcan be prevented.

It is preferable that the weak portion for through hole be one kind ortwo or more kinds selected from a group consisting of a notch, a groove,a slit, and a notch formed at the peripheral edge of either one or bothof the outer through hole and the inner through hole.

Also, the weak portion for through hole may consist of either one orboth of an inner notch formed in the bent portion of the inner panel atthe peripheral edge of the inner through hole and an outer notch formedin the bent portion of the outer panel at the peripheral edge of theouter through hole so as to be opposed to the inner notch.

The invention of an eighth aspect is characterized in that in theinvention of the fifth aspect, a side rail having a channel shape intransverse cross section, which extends in the travel direction of atruck and the rear end of which is positioned in front of a width changeportion, is attached on the upper inside surface of the side panel.

In the truck platform construction described in the invention of theeighth aspect, when an external force acts on the platform from the rearside, stress is concentrated between the width change portion and therear end of side rail.

The invention of a ninth aspect provides an improvement in a truckplatform construction in which a side panel erected at both side edgesof a platform on the back surface of a cab has an outer panel whichconstitutes a side external wall of the platform and an inner panelwhich constitutes a side internal wall of the platform; the outer panelhas an outer bent element formed at the upper edge thereof and an outerthrough hole formed in the outer bent element; the inner panel has aninner through hole formed at the upper part thereof so that the holecenter is aligned with that of the outer through hole; and a fastener isinserted through the outer through hole and the inner through hole tofix the inner panel to the outer panel, whereby a top rail is formed.

The characteristic configuration of the invention of the ninth aspect issuch that either one or both of the inner panel and the outer panel areformed of a synthetic resin, and a recess is formed in the inner panelbetween fastening portions where the top rail is fastened by thefastener.

In the truck platform construction described in the invention of theninth aspect, when an external force acts on the platform from the rearside, stress is concentrated at the recess in the inner panel, so thatthe side panel is easily deformed in this portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an essential portion of a truck of afirst embodiment, viewed from the rear side;

FIG. 2 is a view taken in the direction of arrow A of FIG. 1, showing astate in which a garnish is removed;

FIG. 3 is a sectional view taken along the line B—B of FIG. 2;

FIG. 4 is a sectional view taken along the line C—C of FIG. 2;

FIG. 5 is a sectional view taken along the line D—D of FIG. 2;

FIG. 6 is a sectional view taken along the line E—E of FIG. 5;

FIG. 7 is a sectional view taken along the line F—F of FIG. 6;

FIG. 8 is a sectional view taken along the line G—G of FIG. 2;

FIG. 9 is a sectional view showing a second embodiment of the presentinvention, which corresponds to FIG. 6;

FIG. 10 is a perspective view of an essential portion showing a thirdembodiment of the present invention, which corresponds to FIG. 1;

FIG. 11 is a view taken in the direction of arrow H of FIG. 10;

FIG. 12 is a sectional view taken along the line I—I of FIG. 11;

FIG. 13 is a perspective view of an essential portion of a side panel ina state in which a side rail and a garnish are removed; and

FIG. 14 is a perspective view of an essential portion showing a fourthembodiment of the present invention, which corresponds to FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of the present invention will now be described withreference to the accompanying drawings.

As shown in FIG. 1, a platform 12 is provided on the back surface of acab 11 of a truck 10. At both side edges of a floor panel 13 of theplatform 12, a pair of side panels 14 and 16 are erected. Since thepaired side panels 14 and 16 are symmetrical in the right-and-leftdirection, only the left side panel 14 is explained, and the explanationof the right panel 16 is omitted. The side panel 14 includes an outerpanel 17 constituting a side external wall of the platform 12 and aninner panel 18 constituting a side internal wall of the platform 12(FIGS. 3 and 5).

The outer panel 17, which is formed by bending a metal sheet such as asteel sheet or an aluminum alloy sheet, has an outer panel body 17 afacing to the outside of the truck 10 and an outer bent element 17 bwhich is formed at the upper edge of the outer panel body 17 a andextends horizontally to the inside in the vehicle width direction. Theinner panel 18, which is formed of a synthetic resin such as FRP(fiber-reinforced plastic), has an inner panel body 18 a facing to theinside of the truck 10 and an inner bent element 18 b which is formed atthe upper edge of the inner panel body 18 a and extends horizontally tothe outside in the vehicle width direction. In the case of thisembodiment, a top rail 21 is formed by fixing the outer bent element 17b and the inner bent element 18 b, which is an upper part of the innerpanel 18, to each other with fasteners 19 in a state in which theelement 17 a is lapped on the element 18 a so that the outer bentelement 17 a is positioned over the inner bent element 18 b (FIGS. 2 and5). As the aforementioned fastener 19, a bolt 19 a and a nut 19 b areused. The outer bent element 17 b is formed with outer through holes 17c through which the bolts 19 a are inserted, and the inner bent element18 b is formed with inner through holes 18 c which are opposed to theouter through holes 17 c and through which the bolts 19 a are inserted(FIG. 5). The fastener may be a rivet, not the bolt and nut.

At the rear part of the top rail 21, a width change portion 22 in whichthe width of the top rail 21 changes in a plan view is formed (FIGS. 1to 3). As shown in FIG. 2 in detail, the width change portion 22 has atrapezoidal portion 22 a which is configured so that the width of thetop rail 21 increases gradually to the inside in the vehicle widthdirection toward the rear of the truck and a rectangular portion 22 bwhich is connected to the rear end of the trapezoidal portion 22 a andextends with the width at the rear end of the trapezoidal portion 22 a.On the rear lower surface of the platform 12, that is, on the rear lowersurface of the floor panel 13, a rear reinforcing member 23 constitutinga mount portion M (FIG. 4) of the platform 12 is provided so as toextend in the vehicle width direction (FIGS. 2 and 4). The front part ofthe width change portion 22 is provided at a position at which it doesnot overlap with the rear reinforcing member 23 in a plan view (FIG. 2).In this embodiment, the width change portion 22 is configured so thatthe front part thereof is positioned in front of the rear reinforcingmember 23 and the rear part thereof overlaps with the rear reinforcingmember 23 in a plan view.

A weak portion 24 for change portion is formed in the width changeportion 22 (FIGS. 2 and 3), and a weak portion 26 for through hole isformed at the peripheral edge of the inner through hole 18 c in theinner panel 18 (FIGS. 5 to 7). In this embodiment, the weak portion 24for change portion consists of a rectangular outer opening 24 a formedin the outer bent element 17 b of the width change portion 22 and aninner opening 24 b formed into the same shape as that of the outeropening 24 a at a position opposed to the outer opening 24 a (FIGS. 2and 3). The outer opening 24 a and the inner opening 24 b are configuredso that the front parts thereof are positioned in front of the rearreinforcing member 23 in a plan view, and the rear parts thereof overlapwith the rear reinforcing member 23 in a plan view (FIG. 2). Also, inthis embodiment, the weak portion 26 for through hole consists of asingle notch 26 a formed at the peripheral edge of the inner throughhole 18 c and a groove 26 b one end of which is connected to the notch26 a and the other end of which extends to the inside in the vehiclewidth direction (FIGS. 6 and 7).

The top surface of the top rail 21 is covered with a garnish 27 formedof a synthetic resin such as polypropylene (PP) (FIGS. 3, 5 and 8). Onthe lower surface of the garnish 27, a positioning pin 27 a and lockingmembers 27 b are projectingly provided (FIG. 8). The positioning pin 27a is inserted through positioning holes 17 d and 18 d formed in theouter bent element 17 b and the inner bent element 18 b, and the lockingelements 27 b are locked to engagement holes 17 e and 18 e formed in theouter bent element 17 b and the inner bent element 18 b.

In the truck platform construction configured as described above, whenan external force T (FIG. 1) acts on the platform 12 from the rear side,the external force is applied from a tail gate 28 to the side panel 14via a locking member etc. (not shown). The top rail 21 of the side panel14 has high rigidity, and further forms a portion with higher rigiditybecause the outer panel 17 and the inner panel 18 are fixed to eachother at the upper part of the side panel 14 to form a closedcross-sectional shape. The width change portion 22, which is a portionin which the rigidity changes, is provided on the top rail 21 with highrigidity, and stress is concentrated at this portion to producedeformation, by which energy can be absorbed. If the outer opening 24 aor the inner opening 24 b is provided in the width change portion 22,stress is further concentrated at this portion, and if the notch 26 a orthe groove 26 b is provided, stress is further concentrated at thisportion. Therefore, the side panel 14 is deformed due to the outeropening 24 a or the inner opening 24 b.

Also, a crack is generated in the inner bent element 18 b from the notch26 a through the groove 26 b, and thus the inner through hole 18 c isincreased, so that the nut 19 b comes off the inner through hole 18 c.Thereby, the closed cross-sectional shape formed by the outer panel 17and the inner panel 18 is collapsed, so that the side panel 14 becomeseasy to deform. Further, if the width change portion 22 is configured sothat the front part thereof is positioned in front of the rearreinforcing member 23 and the rear part thereof overlaps with the rearreinforcing member 23 in a plan view, the rigidity of the platform 12can be changed greatly in this portion, so that deformation due tostress concentration is produced, and hence energy can be absorbed. As aresult, the energy of the aforementioned external force T can surely beabsorbed by the deformation of the platform 12, so that the externalforce transmitted to the cab 11 decreases, by which the deformation ofthe cab 11 can be prevented.

Since the top surface of the top rail 21 is covered with the garnish 27,the heads of the bolts 19 a and the outer opening 24 a are invisible.Therefore, the appearance of the platform 12 can be improved, and thetop rail 21 can be prevented from being damaged by a cargo.

FIG. 9 shows a second embodiment of the present invention. In FIG. 9,the same reference numerals are applied to the same elements as thoseshown in FIG. 6.

In this embodiment, a weak portion 46 for through hole formed at theperipheral edge of the inner through hole 18 c in the inner panel 18consists of a plurality of slits 46 a (elongated holes) formed on theoutside of the peripheral edge of the inner through hole 18 c. Each ofthese slits 46 a is formed on the same circumference around the innerthrough hole 18 c into an arcuate shape with a predetermined intervalbeing provided in the circumferential direction. Other constructions arethe same as those of the first embodiment.

In the truck platform construction configured as described above, whenan external force acts on the platform from the rear side, stress isconcentrated between the slits 46 a. Therefore, a crack is generatedbetween the slits 46 a in the inner bent element 18 b, and thus the nutcomes off the inner bent element 18 b together with a part of the innerbent element 18 b in the slit 46 a. Thereby, the closed cross-sectionalshape formed by the outer panel 17 and the inner panel 18 is collapsed,so that the side panel 14 becomes easy to deform. As a result, theenergy of the aforementioned external force T can surely be absorbed bythe deformation of the platform 12, so that the external forcetransmitted to the cab 11 decreases, by which the deformation of the cab11 can be prevented.

FIGS. 10 to 13 show a third embodiment of the present invention. InFIGS. 10 to 13, the same reference numerals are applied to the sameelements as those shown in FIGS. 1, 2 and 5.

In this embodiment, a metallic outer panel 67 of a side panel 64 has anouter panel body 67 a facing to the outside of a truck 60 and an outerbent element 67 b formed at the upper edge of the outer panel body 67 a,and a synthetic resin made inner panel 68 of the side panel 64 has aninner panel body 68 a facing to the inside of the truck 60 and an innerbent element 68 b formed at the upper edge of the inner panel body 68 a(FIGS. 12 and 13). The outer bent element 67 b consists of an outerhorizontal portion 67 c which extends horizontally to the inside in thevehicle width direction from the upper edge of the outer panel body 67 aand a depending portion 67 d which is connected to the tip-end edge ofthe horizontal portion 67 c and extends downward. The inner bent element68 b consists of an inner horizontal portion 68 c which extendshorizontally to the outside in the vehicle width direction from theupper edge of the inner panel body 68 a and an inclined portion 68 dwhich extends downward slantwise from the tip-end edge of the innerhorizontal portion 68 c. Reference numeral 66 in FIG. 10 denotes a sidepanel provided on the right-hand side of a platform 62.

The depending portion 67 d of the outer bent element 67 b is formed withan outer through holes 67 e through which the bolts 19 a of thefasteners 19 are inserted, and at the upper part of the inner panel body68 a, an inner through holes 68 e is formed so that the hole center isaligned with that of the outer through hole 67 e. Specifically, the bolt19 a is inserted through the outer through hole 67 e and the innerthrough hole 68 e, and the nut 19 b is threadedly engaged with theprojecting end portion of the bolt 19 a to fix the outer panel 67 andthe inner panel 68 to each other, by which a top rail 71 is formed (FIG.12). In this case, a gap may be formed between the outer horizontalportion 67 c and the inner horizontal portion 68 c, and also the innerbent element 68 b is not necessarily needed. A weak portion 76 forthrough hole is formed at the peripheral edge of the inner through hole68 e and the outer through hole 67 e (FIGS. 12 and 13). In thisembodiment, the weak portion 76 for through hole consists of an innernotch 76 a formed in a connection portion of the inner panel body 68 aand the inner horizontal portion 68 c at the peripheral edge of theinner through hole 68 e and an outer notch 76 b formed in a connectionportion of the outer horizontal portion 67 c and the depending portion67 d at the peripheral edge of the outer through hole 67 e so as to beopposed to the inner notch 76 a.

On the upper internal surface of the side panel 64, that is, on theinternal surface of the top rail 71, a side rail 77 having a channelshape in cross section, which extends in the travel direction of thetruck 60, is attached by using the bolts 19 a and the nuts 19 b (FIGS.10 to 12). The side rail 77 is provided so that the rear end thereof ispositioned at a predetermined distance in front of a width changeportion 72 (FIG. 11). Further, an opening 62 a is provided at the rearend of the side panel 64 of the platform 62, and a tail gate 78 foropenably closing the opening 62 a is provided in the opening 62 a so asto extend in the vehicle width direction (FIGS. 10 and 11). In a statein which the opening 62 a is closed by the tail gate 78, the inside edgeof the width change portion 72 is gently connected to the side edge ofthe tail gate 78. Specifically, the configuration is such that the rearend of a trapezoidal portion 72 a of the width change portion 72coincides approximately with a side front end 78 a of the tail gate 78,and the length of a rectangular portion 72 b coincides approximatelywith the thickness of the tail gate 78. In other words, a terminal end72 c of spread of the width change portion 72 coincides with the sidefront end 78 a of the tail gate 78 in a state of being closed and a baseend 72 d of the width change portion 72 is connected linearly to theterminal end 72 c of the width change portion 72 (FIG. 11). Thereby, theappearance of the rear end corner portion of the platform 62 can beimproved, and cargoes can easily be put in or taken out through theopening 62 a of the platform 62. Further, since the platform width atthe rear part of the platform 62 is great (the platform shown in FIG. 11is wider than the platform shown in FIG. 2), a large storage space canbe secured. Other constructions are the same as those of the firstembodiment.

In the truck platform construction configured as described above, whenan external force T (FIG. 10) acts on the platform 62 from the rearside, stress is concentrated between the front end of the width changeportion 72 and the rear end of the side rail 77, and also stress isconcentrated at the inner notch 76 a and the outer notch 76 b.Therefore, the side panel 64 is deformed between the front end of thewidth change portion 72 and the rear end of the side rail 77, and alsodeformation is produced at the inner notch 76 a or the outer notch 76 b.As a result, the energy of the aforementioned external force T cansurely be absorbed by the deformation of the platform 62, so that theexternal force transmitted to the cab 11 decreases, by which thedeformation of the cab 11 can be prevented.

FIG. 14 shows a fourth embodiment of the present invention. In FIG. 14,the same reference numerals are applied to the same elements as thoseshown in FIG. 13.

In this embodiment, the outer panel 67 is formed of a metal sheet, theinner panel 68 is formed by a synthetic resin, and a recess 86 is formedin the inner panel 68 between fastening portions where the top rail 71is fastened by the fastener. The bolt of the fastener is insertedthrough the inner through hole 68 e formed at the upper part of theinner panel body 68 a and the outer through hole 67 e formed in thedepending portion 67 d of the outer bent element 67 b. These throughholes 68 e and 67 e are formed in plural number in the truck traveldirection with predetermined intervals being provided. Also, the recess86 is formed between the inner through hole 68 e and the outer throughhole 67 e and the through holes 68 e and 67 e adjacent to these throughholes 68 e and 67 e. This recess 86 has a horizontal portion 86 a whichis formed a predetermined distance lower than the inner horizontalportion 68 c, a front connecting portion 86 b the rear end of which isconnected to the front end of the horizontal portion 86 a, the height ofwhich is gradually increased toward the front of truck, and the frontend of which is connected to the inner horizontal portion 68 c, and arear connecting portion 86 c the front end of which is connected to therear end of the horizontal portion 86 a, the height of which isgradually increased toward the rear of truck, and the rear end of whichis connected to the inner horizontal portion 68 c. Other constructionsare the same as those of the third embodiment.

In the truck platform construction configured as described above, whenan external force acts on the platform 62 from the rear side, stress isconcentrated at the recess 86, so that this portion is deformed. As aresult, the energy due to the aforementioned external force can surelybe absorbed by the deformation of platform, so that the external forcetransmitted to the cab 11 decreases, by which the deformation of the cab11 can be prevented. Also, if the recess 86 is combined with the widthchange portion 22 and the weak portion 24 for change portion (the outeropening 24 a, the inner opening 24 b) shown in FIGS. 2 and 3, the weakportion 26 for through hole (the notch 26 a, the groove 26 b) shown inFIG. 6, the weak portion 46 for through hole (the slit 46 a) shown inFIG. 9, or a weak portion 76 for through hole (the inner notch 76 a, theouter notch 76 b) shown in FIGS. 13 and 14, the deformation of cab 11can be prevented more effectively.

Although the recess 86 is provided in the inner horizontal portion 68 cin the fourth embodiment, the recess may be provided in the inner bentelement 18 b (FIG. 5) in the first embodiment. Furthermore, this recessmay be combined with the width change portion and the weak portion forchange portion (outer opening, inner opening) of the top rail or theweak portion for through hole (notch, groove, slit, notch).

As described above, according to the present invention, theconfiguration is such that the width change portion in which the widthof top rail changes is formed at the rear part of the top rail, and thewidth of the width change portion increases gradually toward the rear ofthe truck. Therefore, when an external force acts on the platform fromthe rear side, stress is concentrated in the front portion of the widthchange portion, and thus the side panel is deformed in this portion. Asa result, the energy of the aforementioned external force can surely beabsorbed by the deformation of the platform, so that the external forcetransmitted to the cab decreases, by which the deformation of the cabcan be prevented.

Also, if the terminal end of spread of the width change portion iscaused to coincide with the side edge of the tail gate in a state ofbeing closed, the appearance of the rear end corner portion of platformcan be improved, and cargoes can easily be put in or taken out throughthe opening at the rear end of the platform. Further, since the platformwidth at the rear part of the platform increases, a large storage spacecan be secured.

If the rear reinforcing member is provided on the rear end lower surfaceof the platform so as to extend in the vehicle width direction, and atleast the front part of the width change portion is formed at a positionat which it does not overlap with the rear reinforcing member in a planview, the rigidity of the platform can be changed greatly at the frontpart of the width change portion, so that deformation due to stressconcentration is produced at the front part of the width change portion,and hence energy can be absorbed.

If the weak portion for change portion is formed in the width changeportion, stress is further concentrated at this portion, so that theside panel is deformed in the weak portion for change portion.

Also, either one or both of the inner panel and the outer panel areformed of a synthetic resin, and the weak portion for through hole isformed at the peripheral edge of either one or both of the inner throughhole in the inner panel and the outer through hole in the outer panel.Thereby, when an external force acts on the platform from the rear side,stress is concentrated at the weak portion for through hole, and hence acrack is generated in this portion, so that the fastener comes off theinner panel, and the side panel becomes easy to deform. As a result, theenergy of the aforementioned external force can surely be absorbed bythe deformation of the platform, so that the external force transmittedto the cab decreases, by which the deformation of the cab can beprevented. Further, the inner panel or the outer panel formed of asynthetic resin has a relatively simple shape, so that the formabilitythereof can be improved.

If the side rail having a channel shape in transverse cross section,which extends in the travel direction of the truck and the rear end ofwhich is positioned in front of the width change portion, is attached onthe upper inside surface of the side panel, when an external force actson the platform from the rear side, stress is concentrated between thefront end of the width change portion and the rear end of the side rail,so that deformation occurs between the front end of the width changeportion and the rear end of the side rail. As a result, as describedabove, the energy of the aforementioned external force can surely beabsorbed by the deformation of the platform, so that the external forcetransmitted to the cab decreases, by which the deformation of the cabcan be prevented.

Further, if either one or both of the inner panel and the outer panelare formed of a synthetic resin, and the recess is formed in the innerpanel between fastening portions where the top rail is fastened by thefastener, when an external force acts on the platform from the rearside, stress is concentrated at the recess in the inner panel, so thatthe side panel is easily deformed in this portion. As a result, theenergy of the aforementioned external force can surely be absorbed bythe deformation of the platform, so that the external force transmittedto the cab decreases, by which the deformation of the cab can beprevented.

1. A truck platform construction comprising a floor panel having twoside edges on the back surface of a cab and side panels erected at eachside edge, each side panel having an outer panel constituting a sideexternal wall of said platform which is formed with an outer bentelement at an upper edge thereof, and an inner panel which is a sideinternal wall of said platform, and a top rail having a finite widthformed by fixing said outer bent element onto said inner panel, whereinsaid top rail has a width change portion at a rear part thereof at whichthe width of said top rail changes, and wherein the width of said widthchange portion increases gradually toward the rear of the truck.
 2. Thetruck platform construction according to claim 1, wherein a weak portionfor change portion is formed in said width change portion.
 3. The truckplatform construction according to claim 1 wherein a terminal end of aspread of said width change portion coincides with a side front end of atail gate for closing an opening at the rear end of said platform. 4.The truck platform construction according to claim 1, wherein a rearreinforcing member is provided on a rear end lower surface of saidplatform so as to extend in a truck width direction, and at least thefront part of said width change portion is formed at a position at whichit does not overlap with said rear reinforcing member in a plan view.